Table A1.

Summary of key event-rates: THN studies in UK and USA.

Study	Trainees’ take-home naloxone rate	Trainees’ follow-up rate at 3 or 6 months (m)	Witnessed overdose rate per 100 person-months (pms)	Experienced overdose rate per 100 person-months (pms)	Reported outcome of witnessed overdose-events
Strang et al., 2008a	160/176	186/239	3.4 {16 in 186∗2.5 m = 465 pms}	0.43 {2 in 186∗2.5 m = 465 pms}	1/16 died. {Two uses by staff}
Gaston et al., 2009		[49/70 but 46/70 were analysed who had 0, 3, 6 m follow-ups]	5.8 [16 in 46∗ 6 m = 276 pms]	0.36 [1 in 46 ∗ 6 m = 276 pms]	1/16 died or 1/7. {already dead; but outcome not known for nine. No trainee used Naloxone at witnessed overdose.}
National Treatment Agency, 2011	417 Naloxone kits supplied to trained carers in 16 pilots costing £98,280 during July 2009 to Feb. 2010 {per kit supplied: £236}.				0/20 died. 18 Naloxone-uses before August 2011, one to prescribee, all survived as did two non-N resuscitations.
HMP Eastwood Park	447 trainees in 1st 6 m, of whom 96 released with Naloxone.				3 “reported” uses of Naloxone.
McAuley et al., 2010	19/23 clients were issued with Naloxone (18 “buddies” also trained)	[17/19 at 6 m]	2.9 [3 in 17∗6 m = 102 pms]		1/3 died; two “saves” via naloxone administrations
Inverness, via Lisa Ross	(120 + 5)/(120 + 40) = 125/160 (Community + prison)				1/19 died in 19 reported uses of naloxone: Aug. 2009 to Jan. 2010 (1st 6 m), one self-use.
Glasgow Naloxone Programme, March 2007 to March 2008 as reported by Shaw and Egan, 2008.	207/221	40/176 user-trainees re-interviewed at 3 months (at least …) and 15/31 family-members: p26	1.6 {2 Naloxone-used overdoses witnessed in 120 pms: 40∗>3 m}:p32	0.83 {1 in at least 40∗ 3 ms  120 pms}	1/11 overdose victims died. {naloxone used for 10, two by staff; re-supply obtained by 2/8 users who had administered naloxone}; 1/11 recent prison-release: p37–39.
Welsh evaluation: cases, Bennett and Holloway, 2011	Over 600 trained during 1-year pilot	644 kits given out by Feb 2011; 48 used.			1/22 died when N-used, or 1/28 replenishments (6 = status NK)
Welsh evaluation: controls, see Bennett & Holloway, 2011	34 users in control areas, of whom 4 reported no events		11.8 [24 overdose events in 34∗ 6 m = 204 pms]	4.9 [10 overdose events in 34∗ 6 m = 204 pms]	1/34 died, see Pages 117–120. Or 1/24 witnessed events
UK summary			5.2 [61 in at least 1167 ms]	1.3 [14 in at least 1065 ms]	7/137 = 5.1% died {1 in 20} or 4/59 = 6.8% died {1 in 15}
Enteen et al., 2010	Between September 2003 and December 2009, 1,942 unduplicated users trained, all prescribed naloxone		399 overdose-events were reported-back by 215 trainees (11%) who had sought refills. Overdoses-events were reason for 399/1020 (40%) refill requests. >0.6 {399+ overdose events in approx. 1,942 ∗ 3 yrs ∗ 12 = 69,912 pms}.		6/363 naloxone-treated overdose victims died; outcome not known for 36 naloxone-administered overdose victims.
Wagner et al., 2010	93 IDU-trainees; 69 agreed to 3 m follow-up, but 3 not trained.	47/66 IDU-trainees followed-up at 3 months.	24.8 {35 overdoses responded to by 22/47 responder-trainees in 3∗47 = 141 pms}. Also note 74.7 {148 overdoses witnessed by 32/66 trainees in 3 m prior to training = 198 pms}	12.1{24 overdoses reported by 10/66 trainees in 3 m prior to training, i.e. in 3 ∗ 66 = 198 pms}	4/30 died {but outcome unknown for 5 overdoses; naloxone administered at 28/35 witnessed overdoses}.
Tobin et al., 2009		[85/250 participants assessed at 6 m]	>9.4 [48/85 witnessed at least 1 overdose in 85 ∗ 6 m = 510 pms]	Not stated	0/22 naloxone-used overdose victims died.
Seal et al., 2005		24/24 IDU-trainees had monthly re-interviews for 6 ms	13.9 [20 witnessed in 24 ∗ 6 m = 144 pms]		0/20 died. Naloxone was administered at 15/20.
Galea et al., 2006		22/25 trainees followed-up at 3 ms	39.4 {11/22 witness 26 overdoses in 22 ∗ 3 m = 66 pms}		1/17 died in specified/most recent overdoses with known outcome, naloxone was used for 10/17.
USA summary			15.0 [129 in 861 pms]	No data prospectively	5/94 = 5.3% died {1 in 19}